Blowouts are nancially damaging for drilling companies and are ecological hazards. Hence
blowout prevention equipment is critical infrastructure for drilling companies. Blowout preventer
valves are important components of blowout prevention equipments and need to be checked
regularly. However, since these valves are often physically inaccessible, they are checked in
batches called test sets. In this paper we present an exact method to check the functional status
of all blowout preventer valves using a minimum number of test sets. We also present a heuristic
method to identify malfunctioning valves if they exist. We illustrate both methods using a real
world example.